Isn't Altoona the home of the famous Horseshoe Curve -- the rail line that loops across a valley?

Now that I think about it a bit, I think they have a minor league baseball team called The Curve.

As Oaknut pointed out, mountains and forests, ... the common motif. Most likely, every lawn to mow will have a slope somewhere, if not everywhere, and it may be steep. The likelihood of finding flat lawns to mow in that area is slim, to none.